Could you please clarify that? It doesn’t seem to mess with the implicit redirects from auto_https if that is what you meant?
Below is what I used to verify, everything is bundled into a single compose.yaml file you can copy/paste, then just run the CLI commands shown at the end 
# For the separate container to reference by name:
networks:
default:
name: custom-network
services:
reverse-proxy:
image: caddy:2.8
container_name: caddy
# Normally this would be `volumes`, but `configs` embeds config for a simple copy/paste `compose.yaml` example
configs:
- source: caddy-config
target: /etc/caddy/Caddyfile
# Support for requests from the Docker host like: `https://example.localhost`
ports:
- "80:80"
- "443:443"
# Containers on this network will resolve these aliases to the IP of this container:
networks:
default:
aliases:
- example.test
configs:
caddy-config:
content: |
{
local_certs
# Docker Compose ENV interpolation feature to toggle auto_https:
${AUTO_HTTPS:-}
}
:80 {
respond "Hello from port 80"
}
# `auto_https disable_redirects` would need require this for HTTP + HTTPS access:
#http://example.test, https://example.test {
example.test, example.localhost {
respond "Hello from {scheme}://{host}"
}
$ docker compose up --force-recreate
# Run a separate container on the same network to curl from and leverage container DNS
$ docker run --rm -it --network custom-network fedora
# HTTP => HTTPS redirect works:
$ curl -L --insecure http://example.test
Hello from https://example.test
# Caddy container also reachable via container_name:
$ curl -L --insecure http://caddy
Hello from port 80
# Repeat but this time with implicit redirects disabled:
$ AUTO_HTTPS='auto_https disable_redirects' docker compose up --force-recreate
$ docker run --rm -it --network custom-network fedora
# HTTP => HTTPS redirect disabled as expected:
$ curl -L --insecure http://example.test
Hello from port 80
# HTTPS still available directly as expected:
$ curl --insecure https://example.test
Hello from https://example.test